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Document Title:
Selenium in a Wyoming Grassland Community Receiving Wastewater from an In Situ Uranium Mine
AUTHOR(S):
Pedro Ramirez Jr Brad Rogers
REPORT NUMBER:
R6/715C /00
PAGES:
1 - 36
PUBLICATION DATE:
September 2000
ABSTRACT:
Water, soil, vegetation, grasshoppers (Family Acrididae), bird eggs and bird livers collected at a 23.5
hectare (58 acres) grassland irrigated with wastewater from an in situ uranium mine (Study Area)
and a reference site in 1998 were analyzed for selenium and other trace elements. Bird surveys were
conducted at the irrigated grassland at the in situ uranium mine to determine species use, relative
abundance and behavior. We observed 23 species of birds using the Study Area. Western
meadowlarks (Sturnella neglecta), red-winged blackbirds (Agelaius phoeniceus), lark buntings
(Calamospiza melanocorys) and horned larks (Eremophila alpestris) were the most common avian
species using the Study Area and were observed feeding and drinking at this site. Meadowlarks, redwinged
blackbirds and lark buntings were observed nesting at the Study Area. Selenium
concentrations in the uranium mine wastewater applied onto the grassland ranged from 340 to 450
-g/L. Selenium in the upper 15 cm (6 in) of soil from the irrigated grassland at the mine ranged
from 2.6 to 4.2 -g/g dry weight (dw). Mean selenium concentrations in soil and water were 5 and
15 times higher at the Study Area than at the reference site. Selenium concentrations in grasses and
grasshoppers ranged from 6.8 to 24 -g/g and 11 to 20 -g/g dw, respectively. Selenium in red-winged
blackbird eggs and livers collected from the Study Area ranged from 13.2 to 22 -g/g and 33 to 53
-g/g dw, respectively, and concentrations were well in excess of toxic thresholds. Two composite
samples of gizzard contents taken from red-winged blackbirds collected at the Study Area had
selenium concentrations of 12 and 83 -g/g dw. Mean selenium concentrations in grasses,
grasshoppers, and bird eggs and livers were 5.8 to 30 times higher at the Study Area than at the
reference site. Elevated selenium concentrations in water, soil, grasshoppers, and red-winged
blackbird eggs and livers collected from the Study Area demonstrate that selenium is being
mobilized and is bioaccumulating in the food chain. Project #: 98-6-6F37-FC
PUBLISHED BY:
U.S. Fish and Wildlife Service
DOCUMENT LINK:
http://www.fws.gov/mountain-prairie/contaminants/papers/r6715c00.pdf, 1 MB
ADDITIONAL LINKS:
U.S. Fish and Wildlife Service - Mountain-Prairie Region, Contaminants Program
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